Many disaster response plans assume that the professional emergency responders - the police, firefighters, ... - will take on a role that is dramatically different from their everyday operations. Fundamentally organizational psychology tells you that it is unrealistic to expect someone to suddenly ignore years of training and experience. Plans should instead anticipate and accommodate this constraint.
Note: This is not a criticism of emergency responders, but a reminder from organizational psychology.
Professional emergency responders - the police, firefighters , ... - tend to be highly resistant to being prepared to use "civilians" to quickly scale-up their handling of a disaster. This resistance is a consequence of their training and their normal mode of operation. For example, at a fire, the fire fighters are the rescuers and everyone else is either a victim or a bystander. Adding outsiders, especially untrained ones, to a team creates substantial risks and may actually decrease the effectiveness of the unit. However, in a disaster, the risk equation changes - the professionals are badly overstretched and there are many lesser tasks that can be handled by citizens where the benefit exceeds the risk.
Effectiveness for police and fire fighters depends upon extensive training to drill in proper procedure and to develop finely-honed reflexes. Police and fire departments recruit people with "bias to action." Disasters and large-scale emergencies create many unexpected situations and require actions that are not covered by normal procedures and sometimes in direct conflict with normal procedures.